To withdraw Bitcoin to fiat on BitMart, you have to sell it for USDT first, and only then will you be able to withdraw your USDT to your bank account as fiat. Furthermore, if you wish to withdraw altcoins, you will first have to swap them for BTC and only then “sell” it for USDT.
To make it simple: Swap the altcoin to BTC, and then to USDT, and then withdraw to your bank account.
You do this by logging into your account, followed by clicking ‘’Sell’’ behind the desired cryptocurrency you want to sell, and then swapping the BTC received for USDT.
When you have USDT, you can sell it to one of BitMart-s third-party partners for the desired fiat currency. Once you have the desired fiat currency in your BitMart account, you can withdraw it to the bank account connected to your BitMart account if you have fully verified your BitMart account and passed the KYC procedure. (Because BitMart does not permit withdrawals without verification)
Alternatively, you can withdraw your crypto from BitMart to Zengo and then sell it at a later time for fiat via Zengo’s fiat offramp services.